Refactor some evil code

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultSetColumn.pm

diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm
index bdb8652..14b35f7 100644 (file)
--- a/lib/DBIx/Class/ResultSetColumn.pm
+++ b/lib/DBIx/Class/ResultSetColumn.pm
@@ -5,6 +5,7 @@ use warnings;
 
 use base 'DBIx::Class';
 
+use Carp::Clan qw/^DBIx::Class/;
 use DBIx::Class::Exception;
 use List::Util;
 
@@ -41,31 +42,33 @@ sub new {
   my ($class, $rs, $column) = @_;
   $class = ref $class if ref $class;
 
-  $rs->throw_exception("column must be supplied") unless $column;
+  $rs->throw_exception('column must be supplied') unless $column;
 
   my $orig_attrs = $rs->_resolved_attrs;
   my $new_parent_rs = $rs->search_rs;
+  my $new_attrs = $new_parent_rs->{attrs} ||= {};
+
+  # since what we do is actually chain to the original resultset, we need to throw
+  # away all selectors (otherwise they'll chain)
+  delete $new_attrs->{$_} for (qw/columns +columns select +select as +as cols include_columns/);
 
   # prefetch causes additional columns to be fetched, but we can not just make a new
   # rs via the _resolved_attrs trick - we need to retain the separation between
   # +select/+as and select/as. At the same time we want to preserve any joins that the
   # prefetch would otherwise generate.
-
-  my $new_attrs = $new_parent_rs->{attrs} ||= {};
   $new_attrs->{join} = $rs->_merge_attr( delete $new_attrs->{join}, delete $new_attrs->{prefetch} );
 
   # If $column can be found in the 'as' list of the parent resultset, use the
   # corresponding element of its 'select' list (to keep any custom column
   # definition set up with 'select' or '+select' attrs), otherwise use $column
   # (to create a new column definition on-the-fly).
-
   my $as_list = $orig_attrs->{as} || [];
   my $select_list = $orig_attrs->{select} || [];
   my $as_index = List::Util::first { ($as_list->[$_] || "") eq $column } 0..$#$as_list;
   my $select = defined $as_index ? $select_list->[$as_index] : $column;
 
   # {collapse} would mean a has_many join was injected, which in turn means
-  # we need to group IF WE CAN (only if the column in question is unique)
+  # we need to group *IF WE CAN* (only if the column in question is unique)
   if (!$new_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) {
 
     # scan for a constraint that would contain our column only - that'd be proof
@@ -80,16 +83,24 @@ sub new {
 
       if ($col eq $select or $fqcol eq $select) {
         $new_attrs->{group_by} = [ $select ];
+        delete $new_attrs->{distinct}; # it is ignored when group_by is present
         last;
       }
     }
+
+    if (!$new_attrs->{group_by}) {
+      carp (
+          "Attempting to retrieve non-unique column '$column' on a resultset containing "
+        . 'one-to-many joins will return duplicate results.'
+      );
+    }
   }
 
   my $new = bless { _select => $select, _as => $column, _parent_resultset => $new_parent_rs }, $class;
   return $new;
 }
 
-=head2 as_query (EXPERIMENTAL)
+=head2 as_query
 
 =over 4
 
@@ -103,8 +114,6 @@ Returns the SQL query and bind vars associated with the invocant.
 
 This is generally used as the RHS for a subquery.
 
-B<NOTE>: This feature is still experimental.
-
 =cut
 
 sub as_query { return shift->_resultset->as_query(@_) }